“That’s how I explain it when we train new employees," Douglas said. "Or, I use the example of picking up the clothes off the floor of your kid’s room before you can do anything else. Cleaning and disinfecting aren’t interchangeable words.”

It’s easy to think there’s no wrong way to clean. And while it doesn’t take a microbiologist to do it correctly, a basic understanding of something referred to as “dwell time,” also sometimes called “contact time” or “kill time,” is necessary, Douglas and other experts say.

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Luckily, information about contact time is available on every cleaning product mass-produced in the United States. To achieve the efficacy of claims such as “kills 99.9% of germs,” just one frequently overlooked step is crucial: Read the instructions, said Todd Clements, chief operating officer for UNX Industries, a chemical manufacturer that supplies nursing homes and hotels with cleaning products.

“All of us are guilty of not reading the backs of the labels,” Clements said.

“As far as I know, there’s no EPA-registered product with specific kill claims against COVID-19 because it’s so new, but it falls under human coronaviruses, so look for the contact time listed for those,” he said.

Clements and Travis FormyDuval, also with UNX, said people may be surprised to learn just how long many top cleaning products must sit — five or 10 minutes is not uncommon. But consumers should be reassured that if they allow a chemical to sit according to instructions, the claim on the front of a product bottle should be achieved. Each product is tested by the Environmental Protection Agency to ensure it does what it says and the instructions have been vetted for accuracy.

“We can’t even change the font on the label unless the EPA approves it,” Clements said.

Joe Rubino, a microbiologist and the director of research and development for Reckitt Benckiser, the parent company of the brand that makes Lysol products, said “sanitize” is another term people also often use incorrectly.

“Cleaning is basically removing dirt and soil. You’re going to remove some of the bacteria but not all of them,” he said. “Disinfecting is a very high level of germ kill, or greater than 99.99%, and you’d really need a few more 9s. Sanitization is another level, the somewhat lower level of 99.9%.”

FormyDuval, who teaches hotel housekeepers best practices, said people can wrongly assume if they use a product for any length of time, they’re going to achieve the efficacy advertised.

When teaching, FormyDuval said he talks about the elements needed to disinfect, which include time, agitation and heat. Agitation is how hard a person must scrub to remove soap stains or grime from surfaces.

“I tell them that just by changing up the routine a little, starting by spraying your chemicals in the bathroom, you can move on to the living portion of the room while you let it sit. When you come back to the shower, it takes less elbow grease, less physical activity to remove any scum, so you’re actually saving time,” FormyDuval said.

Using the same principle at home, he suggested residents spray a chemical in the kitchen, then spray a chemical in the bathroom, select separate towels for each space and head back to the kitchen, leaving each product to sit for the appropriate time. The different rags are so you don’t introduce bathroom germs into the kitchen, or vice versa. Likewise, in the bathroom, it’s best to start at the top and work your way down to the floor.

Erica Marie Hartmann, an assistant professor at Northwestern University, said not every surface needs to be disinfected every time, but it’s a good idea for frequently touched spaces, particularly if sharing a home with someone displaying COVID-19 symptoms.

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“People who are symptomatic, if they’re touching things or coughing on things, those are the things that you want to disinfect more regularly, such as the nightstand, the door handle or whatever they’re commonly interacting with,” Hartmann said. "There are, depending on the surface, tens of billions of microbes.”

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When they’re done using cleaning chemicals, people may be tempted to “wipe away” residue with a wet rag, which is unnecessary because the EPA has determined the chemical is safe to leave behind. But it also won’t prevent or undo disinfection, Rubino said.

“There are a lot of additives to cleaners that can be harmful to health, including endocrine disruptors," said Dr. Susan Buchanan, a University of Illinois at Chicago environmental medicine specialist. “At this time when we’re trying to fight an outbreak, though, those concerns tend to take a back burner.”